how can I write “by the late nineteenth century thought was given to supersonic speeds by the physicist Ernst Mach” in active voice?...

Tobias wolff most likely named his short story "mortals" because the story explores the theme of people coming to terms with the idea that one day they too will die. wanting to find out what their loved ones really think of them. achieving immortalit by being "big people" while they are alive. hoping that they will have accomplished something before they die.